


Honey-Covered Blueberries (Underswap)

by Pickles_Tickle



Series: SwapCest One-Shots and Short Stories (Requests are open) [1]
Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, Ecto-Genitalia (Undertale), Ecto-Penis (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), Incest, Loss of Innocence, Loss of Virginity, M/M, Mating Cycles/In Heat, Monster Heat, Oral Sex, Penetration, Sibling Incest, minor food kink
Language: English
Status: Completed
Published: 2017-05-23
Updated: 2017-05-23
Packaged: 2018-11-04 01:19:48
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 1,489
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10980363
Author URL: https://archiveofourown.org/users/Pickles_Tickle/pseuds/Pickles_Tickle
Summary: Papyrus goes into heat.Sans wants to give him a special surprise~Check this thing out: http://archiveofourown.org/works/11932473/chapters/26971197





	Honey-Covered Blueberries (Underswap)

**Author's Note:**

> Leave requests in the comment section.

It was that time of year again. The time where Papy would shut himself in his room and refuse to come out, save for a shower or the occasional meal. However, he always avoided Sans when he would.

Sans would get so lonely… but at least Alphys would always take care of him during those days!

But this time, she had called in sick, so Sans was downstairs on his own.

He was bored. Then he got an idea. Maybe he could surprise his brother with a honey cake! After all, Papy loves honey, and who  _ doesn’t  _ love cake!? Plus, it would give him a chance to show off his  **magnificent** cooking skills. It’s perfect!

The little skeleton rushed off to the kitchen, grinning like a smol maniac. He pulled out milk, flour, eggs, butter, and sugar. 

Something seemed to be missing…

Sans turned around and began reaching for the top of the fridge, towards Papyrus’s honey stache. Almost…. There…!

He smiled in triumph when he felt his phalanges grab hold of the cardboard crate the honey was held in. Until he lost his balance.

“Whoa!” he cried out in surprise as he and the bottles of honey tumbled to the ground. One broke on top of his head, dousing his skull in sticky sweetness. Some of it poured off his head and into his lap, staining his favorite pair of tights.

He looked around, the noise echoing. He hoped he didn’t wake Papy, that would ruin the surprise!

 

**…**

_ Fuck, _ Papyrus thought, his hands stuffed in his underwear as he grinds down on them.  _ Why do monsters even have heat in the first place…. _

He sighed and groaned into his pillow. Each time, it kept getting harder and harder to please himself. His own hands just weren’t enough anymore.

Three days in, and he’d only come but once, and that was only because of his dream he had before entering heat fully. 

His body felt consumed by fire and the primal urge to create offspring. If he could just sleep it off…. Yet every time he’d closed his eyes and tried to ignore the arousing burn, he’d only find his hands pinching his sacrum once again. His magic hasn’t even formed, making it even more difficult to masturbate. 

He groaned and wrapped a hand around his spine. Pleasuring somewhat, yet totally predictable. He knew it was coming, and couldn’t relish in the surprise that comes from having a partner stroke you.

Then, he heard a crashing sound from the kitchen. He could have sworn Sans was with Alphys…

Debating for a minute, he wondered how risky it would be to stay put versus go out in his condition. On the one hand, it’d take his mind off his unbearable heat, but on the other…. There might be a dangerous intruder.

Finally, he makes up his mind and gets up, pulling on his loose black sweatpants and equally loose orange hoodie. Then Papyrus ventured downstairs, leaning on the rail.

The noises came from the kitchen. It sounded as if someone was whimpering slightly, trying not to cry, and shuffling noises as if something being placed inside of a container. 

“Hello?” Papyrus calls.

There was a small squeal that sounded like his brother. 

“Sans? Is that you? Why aren’t you at Al-” his question cut short when he saw the scene before him.

Sans was hurriedly placing the box of honey bottles on the shelf, reaching up high, his bare and naked pelvis in plain view. His skull was covered in pale amber liquid, as was the bare lower bone.

This was enough to finally summon his heat magic, a shaft forming and pressing against the front of his pants.

“P-Papy! I-I, uh- Alphys was sick, a-and I j-just wanted to… to make you a surprise… b-but I messed it up...” he teared up and sniffled at the mess he made.

The older skeleton shook the thoughts from his head and walked over, trying to ignore the arousing image of Sans half naked and covered in honey.

He wrapped his arms around him, picking him up. “Oh, Sans…. You didn’t ruin the surprise.”

Sans rubbed his eye sockets. “I… I didn’t?”

“No, of course not. In fact… you gave me an even better one~” Papyrus couldn’t help himself as he ran his tongue up Sans’ face, licking off the sweet fluids.

Sans made a strangled yelp sound and snapped his gaze to his brother’s face. “Brother? What are you doing!?”

“Just cleaning you up.” Papyrus swallowed the sweet honey as Sans blushed.

“B-but Papy!”

“Is something wrong?”

“....no.”

“Okay then.” He hesitated a moment. “Sans…?”

“Yes, brother?”

Papyrus looked at him seriously. “Would it be okay if we tried something new?”

**...**

 

“Tell me when to stop, okay?” Papyrus explains as he wraps his hand around Sans’ backbone.

It arched into his hand as he gasped and nodded.

Using slow, calculated strokes, Papyrus began working. Sans shook and moaned, panting. His eyes drooped down to halfway. 

“Pah… Pappy?~ Wh-what is this…. Nnh~... this feeling?”

“Is it bad? Do you want me to stop?”

Sans stopped and thought for a moment. He felt so good… but this felt weird…. Sort of… not  _ wrong _ , exactly, just kind of like it shouldn’t be happening? And yet, he didn’t want it to stop, he truly didn’t.

“You don’t have to. K-keep going.”

Papyrus looked relieved, and then he went up closer to Sans. Stripping off the last of their his clothes, Sans’ small pelvis came into view. The smaller skeleton grew self-conscious when Papyrus stared at the swirling magic.

“Papy…?”

“Can I keep going?”

Sans gave the permissive nod, and Papyrus dipped two fingers just behind his pubic crest, rubbing the bone.

The feeling flooded Sans with the weird new warmth, and it made him moan in a lewd manner. He wanted more.

He  _ needed  _ more.

Papyrus massaged the magic and bones, until Sans felt something wet between his legs. Curious, he looked down to see plump lips dripping in a bluish white residue.

“Oh, Sans….” Papyrus breathed. “It’s beautiful.”

“Really? What is it?”

“Tell me how this feels,” Papyrus says as he pulls back. His face hovers in front of Sans’....  _ thing, _ hot air being blown on it. He moans softly.

Papyrus summons his tongue, and licks upwards across the blue lips. Oh stars, that felt fantastic.

Sans jolts and lets out a high-pitched whine, his toes curling.

Papyrus licks it again, with the same results.

Soon, he seemed to want more, and sat up, a bright orange… something standing firm and hard into the air. He pumps it a few times while Sans watches, mesmerized.

He started squirming, the heat in his mound suddenly being ignored. “Papy,” he whines.

“Patience, Sa-Sans. I’m almost ready.”

He positions himself over his younger brother and leans down, kissing his neck.

“Ready?”

Sans nods, though he is unsure what Papyrus means by ‘ready’.

Suddenly, his hips snap forward, the bright orange rod of magic being stuffed into the wet blue mound, resulting in pleased cries from both skeletons.

“P-PAPY!” Sans cried out, gasping in pleasure.

Papyrus sat still for a moment, Sans taking the break to adjust, before slowly pulling out.

They both let out slow moans.

Then he pushed back in again, and started a smooth, slow rhythm, Sans’ whines and moans seemingly encouraging him on.

He moaned as the soft velvety warmth enveloped his aching cock, but oh  _ stars _ it felt so good.

He began to move faster, causing Sans to whine and squirm, clenching and unclenching his fists.

“P-Papy!~” moans the smaller skeleton.

Papyrus only grips him closer, friction being his only goal as he cants his hips faster.

He was nearing climax, they both were.

Sans felt like he was going to pee himself. He blushes because the organ he’d conjured involuntarily was throbbing in that oh so wonderful pleasure, but he felt the pressure building up.

He moaned again, but it was broken and got caught in his throat. 

“PAPY!” he whines, more blue liquid spurting from his pussy.

Papyrus cried out and slammed himself into his brother, both crying out as he spills his hot seed into him.

Sans couldn’t help but clench around him as he gripped Papyrus’s arms tightly, and cried into his chest as the pressure exploded. His world went black, then white, and stars danced around his vision as silent noise roared in his ears.

He couldn’t help it. It felt so good he screamed from the pleasure, hot tears spilling out of his eyes. His hips bucked wildly, but then suddenly….

The world was back, and his bones felt like lead. His throat hurt from screaming, but he still felt good. Eyelids drooping, he looked up at Papyrus, who had pulled out and was stroking the top of his skull.

“That was the best surprise ever, Sans,” he praised, just before Sans fell asleep in his arms.


End file.
